Thanks, Mark, for your comment. The Navy tried one more DC turboelectric drive submarine, the modified Sturgeon class Glenard P. Lipscomb. It was very quiet, but again slow, like Tullibee. DC does not scale well as power is increased.
However, the upcoming Columbia class SSBN class, the Ohio replacements, are currently planned to have AC turbo electric drive. The AC electric motors will be more compact than the massive DC versions, and much quieter than steam turbines and gear trains currently in use. At one point, later block versions of the Virginia class were also planned to have turbo electric drive, but I think that was dropped.